The present invention relates to a wind power plant with a rotor which includes rotor blades adjustably mounted on a rotor hub. In particular, the invention relates to a rotor blade adjusting drive for adjusting the pitch angle of the rotor blades of such a wind power plant, comprising a drive train connectable at the output end with the rotor blade and/or a bearing member supporting the rotor blade, and a spring accumulator connectable with the drive train, which includes a spring accumulator shaft, a spring accumulator housing and a spring means which can be tensioned by rotating spring accumulator shaft and spring accumulator housing relative to each other, wherein the spring accumulator shaft and/or the spring accumulator housing can be uncoupled from the drive train and is rotatable with respect to the same for biasing the spring means.
For power control, wind power plants usually employ an adjustment of the rotor blades. The individual rotor blades can rotatably be connected with the rotor hub via large bearings, so that the rotor blades can be rotated about their longitudinal axis and hence their pitch angle can be adjusted. For adjusting the rotor blades, electric drive motors mostly are used, which adjust the rotatable ring of the rotor blade bearing and hence the rotor blades themselves via a transmission and an output pinion.
If an interruption or some other malfunction of the drive motors occurs in the power supply of the drive motors, the rotor blades must be brought into a safe position for safety reasons. In many cases, electric batteries are provided for this purpose, in order to achieve an emergency supply of the drive motors. On the other hand, mechanical spring accumulators have already been proposed for such cases, in order to effect the return of the rotor blades into a neutral position for safety reasons. To enable these mechanical spring accumulators to effect the adjustment of the rotor blades, the springs of the spring accumulators must be biased before operation. For this purpose, it has been proposed to uncouple the inside spring accumulator shaft from the drive train and rotate the same with a suitable tool, until the desired bias is achieved. Upon application of the bias, the spring accumulator shaft is connected with the drive train of the rotor blade adjusting drive by means of a clutch. During the entire winding operation, however, a considerable risk consists in that in the case of improper handling the springs of the spring accumulator strike back uncontrolled and hurt the operator with the winding tool.